JP3925153B2 - Magnetron - Google Patents

Magnetron Download PDF

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Publication number
JP3925153B2
JP3925153B2 JP2001326281A JP2001326281A JP3925153B2 JP 3925153 B2 JP3925153 B2 JP 3925153B2 JP 2001326281 A JP2001326281 A JP 2001326281A JP 2001326281 A JP2001326281 A JP 2001326281A JP 3925153 B2 JP3925153 B2 JP 3925153B2
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Japan
Prior art keywords
vane
anode
magnetron
diameter
efficiency
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JP2001326281A
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Japanese (ja)
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JP2003132809A (en
Inventor
健 石井
貴典 半田
正幸 相賀
なぎさ 桑原
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Panasonic Corp
Panasonic Holdings Corp
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Panasonic Corp
Matsushita Electric Industrial Co Ltd
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Priority to JP2001326281A priority Critical patent/JP3925153B2/en
Priority claimed from EP02255773A external-priority patent/EP1286379B1/en
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【0001】
【発明の属する技術分野】
本発明は、電子レンジ等のマイクロ波応用機器に用いられるマグネトロンに関する。
【0002】
【従来の技術】
マグネトロンはマイクロ波を発生する電子管であり、発振効率が比較的高く大出力化が容易なことから、電子レンジをはじめとするマイクロ波応用機器のマイクロ波発生源として広く用いられている。
【0003】
以下に従来のマグネトロンについて説明する。
【0004】
図7は従来の一般的な電子レンジに使用されるマグネトロンの断面図である。図7に示されるように、マグネトロンの中央部には陰極部が配設されており、この陰極部は、フィラメント1、その両端にエンドハット2、3を介して接続されたセンターリード4とサイドリード5によって構成されている。また、陽極円筒6と、この陽極円筒6の内周面からフィラメント1に向かって突出し、その先端がフィラメント1と所定間隔を保つように配設された複数個のベイン7とで陽極部が形成されている。
【0005】
陽極円筒6の管軸方向両端部には、略同一形状ですり鉢状の一対の磁極9,10が相対向して設けられており、さらにこの磁極9,10のそれぞれの管軸方向外方には、フィラメント印加用電力およびマグネトロン駆動用高電圧を供給するための入力部11と、マイクロ波を伝送し放射するための出力部12とが設けられてマグネトロンの本体部を構成している。
【0006】
さらには、一対の環状永久磁石13,14が、それぞれ一方の磁極面を磁極9,10に、他方の磁極面を強磁性体から成る断面がコ字状の枠状継鉄15,16にそれぞれ磁気的に結合されて構成された磁気回路により、ベイン7とフィラメント1との間に形成される電子運動空間17に磁界を供給している。なお、陽極構体の任意のベインにはマイクロ波出力用のアンテナリード18の一端が接続され、他端が外方へ導出されている。
【0007】
従来のマグネトロンの本体部における主な仕様および寸法としては、発振周波数が2,450MHz帯で、ベイン7の数量は10個、ベイン7の陰極側先端部で形成される内接円の直径φaが9.0mm、コイル状フィラメント1の外径φcが3.9mm、ベイン7の寸法は管軸方向高さHが9.5mm、厚さTが2.0mm、また隣り合うベイン7の陰極側先端部の相互間隔Gが0.9mmであり、GとTとの比G/(G+T)=0.31であり、電子運動空間17における磁束密度は、一対の磁極9,10間の中央部でセンターリード4上における磁束密度を測定すると0.195±0.010テスラである。
【0008】
このような構成のマグネトロンにおいて、フィラメント1を加熱し、陰極部と陽極部との間に所定の電圧を印加することによって、フィラメント1からベイン7に向かって放出された電子は、電子運動空間17内の磁界によってフィメント1の周囲を周回しマイクロ波エネルギーを発生させる。このマイクロ波エネルギーは、ベイン7の一つと電気的に結合されたアンテナリード18によって出力部12に伝送され、電子レンジ等の庫内へ放射される。この時のマグネトロンの発振効率は、陽極部と陰極部との間に印加された直流入力(陽極電圧×陽極電流)と、出力部12から放射されたマイクロ波電力の測定値から算出され、従来の代表的なマグネトロンの特性としては、陽極電圧4.5kV、陽極電流300mAでマイクロ波電力約1kWを出力させることにより、発振効率75%が得られていた。
【0009】
ここで、マグネトロンの発振効率は電子の運動効率である電子効率と、ジュール損や誘電体損等の回路定数が関係する回路効率との積で決定される。つまり、発振効率η=電子効率ηe×回路効率ηcで表される。
【0010】
このうち、電子効率ηeは、陽極電圧との関係では(数1)で表され、陽極電圧を高くすると電子効率ηeが向上することが公知となっている。
【0011】
【数1】
【0012】
また別の観点から、電子効率ηeは、磁束密度との関係では(数2)で表され、磁束密度を大きくすると電子効率ηeが向上することが公知となっている。
【0013】
【数2】
【0014】
【発明が解決しようとする課題】
近年の世界的な省エネ化指向から発振効率の向上が要求されてきたことを機にマグネトロンの発振効率改善の必要性が生じてきたため、従来のマグネトロンでは、陽極電圧を高くして且つ電子運動空間に供給される磁束密度を大きくすることによって発振効率を向上させていた。しかしながら、陽極電圧を高くするとマグネトロン駆動用電源を高電圧用のものに変更し、また陽極電圧を高くする必要性からマグネトロンとその周辺部品の絶縁耐圧を高くしなければならず、そのためコストアップを招くという課題を有していた。
【0015】
本発明は上記従来の課題を解決するもので、電子効率を改善し、発振効率を向上させる高効率のマグネトロンを提供することを目的とする。
【0016】
【課題を解決するための手段】
この課題を解決するために本発明の請求項1に記載のマグネトロンは、陽極円筒と、この陽極円筒の内壁面に固着された複数個のベインとで形成される陽極部と、前記陽極部の同軸的中心部に設けられたコイル状フィラメントからなる陰極部と、前記陽極部の管軸方向上下に配設された一対の磁極と、この一対の磁極と磁気的に結合配置されて磁気回路を構成する環状永久磁石と、前記磁極の各管軸方向外方にそれぞれ配設された入力部と出力部とを具備し、前記陽極部を構成するベイン先端部の内接円の直径が7.5〜8.5mmの範囲内であり、前記コイル状フィラメントの外径が3.4〜3.6mmの範囲内であり、かつ前記ベインの隣り合う陰極側先端部の相互間隔Gとベインの厚さTとの比をG/(G+T)=0.20〜0.25としている。
【0017】
これにより、従来の陽極電圧のままでも発振効率を向上させることができる。
【0020】
【発明の実施の形態】
以下本発明の一実施の形態について、図面を参照しながら説明する。なお従来例と同一構成要素については同一符号が付してある。
【0021】
図1(a)は本発明のマグネトロンの要部拡大断面図を示す。各部の寸法は、2個の環状永久磁石19、20の外径をD1、D3、内径をD2、D4、厚さをL1、L2、ベイン陰極側先端内接円の直径をφa、コイル状フィラメント1の外径をφc、ベイン7の管軸方向寸法をHで表した。また、図1(b)は、ベイン7を管軸方向すなわち図1(a)のA方向から見たときの陽極部を示し、隣り合うベインの陰極側先端部の相互間隔をG、ベインの厚さをTで表した。本実施の形態では、2個の環状永久磁石は材質および寸法ともに同じものを用いた。そして本発明者らは、(数1)にしたがってマグネトロンの発振効率を上げることを目的として、マグネトロンの磁束密度を従来のマグネトロンにおける0.195±0.010テスラよりも大きくし、種々の実験による試行錯誤の結果、0.250±0.010テスラとした。この値を得るためにSrフェライト製(TDK株式会社製FB5N)環状永久磁石は、外径D1、D3を55mmから80mmにした。なお、環状永久磁石の内径D2、D4および厚さL1、L2は、従来と同じである。
【0022】
本発明では、発振効率を上げるために、陽極電圧Vaを大きくすることと同じ効果を得る方法として、ベイン陰極側先端部内接円の直径φaを小さくすることによって陽極部と陰極部の間の電界を強くする方法を採用し実験を行った。そしてまた、電界分布を詳細に検討するため、ベインの陰極側先端部の相互間隔Gとベインの厚さTの検討を行った。
【0023】
図2は、ベイン陰極側先端部内接円の直径φaを変えたときに、従来と同じ陽極電圧Vaを4.5kVで発振させるために要した磁束密度の大きさについての実験結果を示す。図に示されるように、ベイン陰極側先端部内接円の直径φaが8.5mm、8.0mm、7.5mmのときに、磁束密度はそれぞれ0.220±0.010テスラ、0.250±0.010テスラ、0.290±0.010テスラに大きくすることが必要であった。しかしながら、このときのマグネトロンの発振効率は、図3に示されるように10個の平均値でそれぞれ75.4%、76.0%、75.6%であり、従来の75.0%よりもわずかに大きくなるに過ぎなかった。比較のため、図2および図3に従来のマグネトロンにおけるベイン陰極側先端部内接円の直径φaが9.0mmのものについても磁束密度(0.195±0.010テスラ)と発振効率(75.0%)を記載した。なお、本実施の形態では、後述する図6に示される実験を除いて管軸方向高さHは従来と同じ9.5mmとし、またすべての実験についてベイン7の数量は従来と同じ10個とした。以上述べたように、電子運動空間内の電界を強くし磁束密度を大きくすることによって、マグネトロン発振効率をわずかに向上させることができた。しかし、十分なものではなかった。
【0024】
このため、さらに発振効率を向上させるための検討を行った。そして、電界および磁束密度の大きさを検討するだけでは不十分であるとの考えに立ち、電子運動空間内の軸方向での電界と磁束密度の分布を考慮することにし、ベイン先端部の内接円直径φaに対してコイル状フィラメント1の外径φcを変化させた。そのときの発振効率の結果を図4に示す。図4には、図2に示されるようにベイン先端部の内接円直径φaを7.5mm,8.0mm,8.5mmとし、磁束密度はそれぞれ0.290±0.010テスラ、0.250±0.010テスラ、0.220±0.010テスラとしたものについて、コイル状フィラメント1の外径φcを3.9mmから3.8mm,3.7mm,3.6mm,3.4mmと変化させたときの発振効率の結果を示す。比較のために、従来例であるφa9.0mm、φc3.9mmを黒丸(●)で示し、発振効率は75%であった。三角(△)は外径φcを3.9mm,3.8mm,3.7mmと変えたときを示し、それらの発振効率はいずれも76%であった。また、白丸(〇)は外径φcを3.6mm,3.4mmに変えたときを示し、それらの発振効率はいずれも77%であった。以上の結果から、ベイン先端部の内接円直径φaを7.5mm,8.0mm,8.5mmとし、磁束密度はそれぞれ0.290±0.010テスラ、0.250±0.010テスラ、0.220±0.010テスラとしたものについて、外径φcが3.4mmから3.6mmまでの範囲で、発振効率が77%になることがわかった。
【0025】
さらにまた、電子運動空間内の電界の分布について詳細に検討することにし、ベインの陰極側先端部の相互間隔Gとベインの厚さTの検討を行った。図5には、ベイン先端部の内接円直径φaを8.0mm、磁束密度を0.250±0.010テスラ、コイル状フィラメント1の外径φcを3.6mmにしたときに、GとTの比G/(G+T)をパラメータとして発振効率を測定した結果を示す。G/(G+T)=0.20,0.22,0.25のときに発振効率は試料10個の平均値でそれぞれ77.8%,78.1%,77.5%に向上した。
【0026】
また、ベインの高さ方向に電界が発生すると発振効率が低下する原因となることから、ベイン7の管軸方向高さHについて検討をした。図6には、図2から図5までに示された結果のうち、発振効率が最高になるときの条件において、すなわち磁束密度が0.250±0.010テスラ、ベイン先端部の内接円直径φaが8.0mm、コイル状フィラメント1の外径φcを3.6mm、G/(G+T)=0.22のときにベイン7の管軸方向高さHを検討した結果を示す。この図からベイン7の管軸方向高さ寸法Hは9.0mm以上であれば発振効率がほぼ78%となることがわかった。
【0027】
(表1)には、本発明および従来のマグネトロンを比較して、入力した陽極電圧4.5kVおよび陽極電流300mAにおける出力、発振効率の測定結果を示す。
【0028】
【表1】
【0029】
【発明の効果】
以上詳述したように本発明は、磁束密度を大きくし、電子運動空間に関連するマグネトロン各部の寸法を最適化することによって、陽極電圧を高くすることなく電子効率ηeを改善し、発振効率ηを大幅に向上することができる高効率型マグネトロンを提供することができる。
【図面の簡単な説明】
【図1】(a)は本発明のマグネトロンの要部拡大断面図
(b)は本発明の隣り合うベインの陰極側先端部の相互間隔Gとベインの厚さTを示す図
【図2】本発明についてベイン先端部の内接円の直径と磁束密度との関係を従来例と比較して示す図
【図3】図2に示されるベイン先端部の内接円の直径と磁束密度における発振効率を示す図
【図4】本発明についてベイン先端部の内接円の直径φaとコイル状フィラメントの外径φcとの発振効率の関係を従来例と比較して示す図
【図5】本発明についてベイン陰極側先端部の相互間隔Gと厚さTとの比と発振効率の関係を従来例と比較して示す図
【図6】本発明のベイン管軸方向高さと発振効率の関係を示す図
【図7】従来のマグネトロンの断面図
【符号の説明】
1 コイル状フィラメント
4 センターリード
6 陽極円筒
7 ベイン
9 磁極
10 磁極
17 電子運動空間
19 環状永久磁石
20 環状永久磁石
D1 環状永久磁石の外径
D2 環状永久磁石の内径
D3 環状永久磁石の外径
D4 環状永久磁石の内径
L1 環状永久磁石の厚さ
L2 環状永久磁石の厚さ
φa ベイン陰極側先端内接円の直径
φc コイル状フィラメントの外径
G ベインの隣り合う陰極側先端部の相互間隔
T ベインの厚さ
H ベインの管軸方向寸法
[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a magnetron used in microwave application equipment such as a microwave oven.
[0002]
[Prior art]
A magnetron is an electron tube that generates microwaves, and since it has a relatively high oscillation efficiency and can easily increase the output, it is widely used as a microwave generation source for microwave application equipment such as microwave ovens.
[0003]
A conventional magnetron will be described below.
[0004]
FIG. 7 is a cross-sectional view of a magnetron used in a conventional general microwave oven. As shown in FIG. 7, a cathode part is disposed at the center of the magnetron. This cathode part is composed of a filament 1 and a center lead 4 connected to both ends of the magnetron via end hats 2 and 3 and a side. A lead 5 is used. Further, an anode portion is formed by the anode cylinder 6 and a plurality of vanes 7 that protrude from the inner peripheral surface of the anode cylinder 6 toward the filament 1 and whose tips are arranged at a predetermined distance from the filament 1. Has been.
[0005]
A pair of mortar-shaped magnetic poles 9 and 10 having substantially the same shape are provided opposite to each other in both ends of the anode cylinder 6 in the tube axis direction. Is provided with an input unit 11 for supplying filament application power and a magnetron driving high voltage, and an output unit 12 for transmitting and radiating microwaves to constitute a main body of the magnetron.
[0006]
Further, the pair of annular permanent magnets 13 and 14 has one magnetic pole surface as the magnetic poles 9 and 10 and the other magnetic pole surface as the frame-shaped yokes 15 and 16 each having a U-shaped cross section made of a ferromagnetic material. Magnetic fields are supplied to an electron motion space 17 formed between the vane 7 and the filament 1 by a magnetic circuit configured to be magnetically coupled. One end of a microwave output antenna lead 18 is connected to an arbitrary vane of the anode structure, and the other end is led out to the outside.
[0007]
The main specifications and dimensions of the main body of the conventional magnetron are as follows: the oscillation frequency is 2,450 MHz, the number of vanes 7 is 10, and the diameter φa of the inscribed circle formed at the cathode side tip of vane 7 is 9.0 mm, the outer diameter φc of the coiled filament 1 is 3.9 mm, the dimensions of the vane 7 are the tube axis height H of 9.5 mm, the thickness T of 2.0 mm, and the cathode side tip of the adjacent vane 7 The distance G between the portions is 0.9 mm, the ratio G / T is G / (G + T) = 0.31, and the magnetic flux density in the electron motion space 17 is at the center between the pair of magnetic poles 9 and 10. When the magnetic flux density on the center lead 4 is measured, it is 0.195 ± 0.010 Tesla.
[0008]
In the magnetron having such a configuration, when the filament 1 is heated and a predetermined voltage is applied between the cathode portion and the anode portion, electrons emitted from the filament 1 toward the vane 7 are converted into an electron motion space 17. The surrounding magnetic field of the Fiment 1 is generated by the internal magnetic field to generate microwave energy. This microwave energy is transmitted to the output unit 12 by an antenna lead 18 electrically coupled to one of the vanes 7 and is radiated into a cabinet such as a microwave oven. The oscillation efficiency of the magnetron at this time is calculated from the measured value of the direct-current input (anode voltage × anode current) applied between the anode part and the cathode part and the microwave power radiated from the output part 12. As a typical magnetron characteristic, an oscillation efficiency of 75% was obtained by outputting a microwave power of about 1 kW at an anode voltage of 4.5 kV and an anode current of 300 mA.
[0009]
Here, the oscillation efficiency of the magnetron is determined by the product of electronic efficiency, which is the kinetic efficiency of electrons, and circuit efficiency related to circuit constants such as Joule loss and dielectric loss. That is, the oscillation efficiency η = electronic efficiency ηe × circuit efficiency ηc.
[0010]
Among these, the electronic efficiency ηe is expressed by (Equation 1) in relation to the anode voltage, and it is known that the electron efficiency ηe is improved when the anode voltage is increased.
[0011]
[Expression 1]
[0012]
From another point of view, the electronic efficiency ηe is expressed by (Equation 2) in relation to the magnetic flux density, and it is known that increasing the magnetic flux density improves the electronic efficiency ηe.
[0013]
[Expression 2]
[0014]
[Problems to be solved by the invention]
The need to improve the oscillation efficiency of the magnetron has arisen due to the demand for improved oscillation efficiency from the recent trend toward energy saving in the world, so in the conventional magnetron, the anode voltage is increased and the electron motion space is increased. The oscillation efficiency has been improved by increasing the magnetic flux density supplied to. However, if the anode voltage is increased, the magnetron drive power supply must be changed to one for high voltage, and the insulation voltage between the magnetron and its peripheral parts must be increased due to the need to increase the anode voltage, which increases costs. Had the problem of inviting.
[0015]
The present invention solves the above-described conventional problems, and an object thereof is to provide a highly efficient magnetron that improves electronic efficiency and improves oscillation efficiency.
[0016]
[Means for Solving the Problems]
In order to solve this problem, a magnetron according to a first aspect of the present invention includes an anode cylinder, an anode section formed of a plurality of vanes fixed to an inner wall surface of the anode cylinder, and the anode section. A cathode portion made of a coiled filament provided in the coaxial central portion, a pair of magnetic poles disposed above and below the anode portion in the tube axis direction, and a magnetic circuit that is magnetically coupled to the pair of magnetic poles. An annular permanent magnet, and an input portion and an output portion respectively disposed on the outer sides in the tube axis direction of the magnetic pole, and the diameter of the inscribed circle of the vane tip portion constituting the anode portion is 7. 5 to 8.5 mm, the outer diameter of the coiled filament is in the range of 3.4 to 3.6 mm, and the gap G between the adjacent cathode side tips of the vane and the thickness of the vane The ratio with T is G / (G + T) = 0.20-0.25 It is.
[0017]
Thereby, the oscillation efficiency can be improved even with the conventional anode voltage.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected about the same component as a prior art example.
[0021]
Fig.1 (a) shows the principal part expanded sectional view of the magnetron of this invention. The dimensions of each part are as follows: the outer diameters of the two annular permanent magnets 19 and 20 are D1 and D3, the inner diameters are D2 and D4, the thicknesses are L1 and L2, the diameter of the inscribed circle on the vane cathode side is φa, and the coil filament The outer diameter of 1 was represented by φc, and the dimension of the vane 7 in the tube axis direction was represented by H. FIG. 1 (b) shows the anode portion when the vane 7 is viewed from the tube axis direction, that is, the A direction in FIG. 1 (a), and the interval between the cathode side tip portions of adjacent vanes is G. The thickness was represented by T. In the present embodiment, the same material and dimensions are used for the two annular permanent magnets. The inventors of the present invention have made the magnetic flux density of the magnetron larger than 0.195 ± 0.010 Tesla in the conventional magnetron for the purpose of increasing the oscillation efficiency of the magnetron according to (Equation 1), and by various experiments. As a result of trial and error, it was set to 0.250 ± 0.010 Tesla. In order to obtain this value, the outer diameters D1 and D3 of Sr ferrite (FB5N manufactured by TDK Corporation) annular permanent magnets were changed from 55 mm to 80 mm. The inner diameters D2 and D4 and the thicknesses L1 and L2 of the annular permanent magnet are the same as the conventional one.
[0022]
In the present invention, as a method of obtaining the same effect as increasing the anode voltage Va in order to increase the oscillation efficiency, the electric field between the anode part and the cathode part is reduced by reducing the diameter φa of the inscribed circle on the vane cathode side tip part. The experiment was carried out using the method of strengthening. In addition, in order to examine the electric field distribution in detail, the mutual spacing G between the cathode side tips of the vane and the thickness T of the vane were examined.
[0023]
FIG. 2 shows the experimental results on the magnitude of the magnetic flux density required to oscillate the same anode voltage Va at 4.5 kV when the diameter φa of the vane cathode side tip inscribed circle is changed. As shown in the figure, when the diameter φa of the inscribed circle on the vane cathode side tip is 8.5 mm, 8.0 mm, and 7.5 mm, the magnetic flux densities are 0.220 ± 0.010 Tesla and 0.250 ±, respectively. It was necessary to increase it to 0.010 Tesla and 0.290 ± 0.010 Tesla. However, the oscillation efficiency of the magnetron at this time is 75.4%, 76.0%, and 75.6%, respectively, as shown in FIG. It was only slightly larger. For comparison, the magnetic flux density (0.195 ± 0.010 Tesla) and the oscillation efficiency (75.75) are also shown in FIGS. 2 and 3 where the diameter φa of the inscribed circle on the vane cathode side in the conventional magnetron is 9.0 mm. 0%). In this embodiment, except for the experiment shown in FIG. 6 to be described later, the height H in the tube axis direction is 9.5 mm, which is the same as the prior art, and the number of vanes 7 is 10, the same as the conventional one, for all experiments. did. As described above, the magnetron oscillation efficiency was slightly improved by increasing the electric field in the electron motion space and increasing the magnetic flux density. However, it was not enough.
[0024]
For this reason, investigations were made to further improve the oscillation efficiency. Then, considering that the magnitude of the electric field and the magnetic flux density is not sufficient, the distribution of the electric field and the magnetic flux density in the axial direction in the electron motion space is considered, and the inside of the vane tip is considered. The outer diameter φc of the coiled filament 1 was changed with respect to the contact circle diameter φa. The result of the oscillation efficiency at that time is shown in FIG. In FIG. 4, as shown in FIG. 2, the inscribed circle diameter φa of the vane tip is set to 7.5 mm, 8.0 mm, and 8.5 mm, and the magnetic flux densities are 0.290 ± 0.010 Tesla, 0.2 mm, respectively. For the ones with 250 ± 0.010 Tesla and 0.220 ± 0.010 Tesla, the outer diameter φc of the coiled filament 1 changed from 3.9 mm to 3.8 mm, 3.7 mm, 3.6 mm, 3.4 mm. The result of the oscillation efficiency is shown. For comparison, φa 9.0 mm and φc 3.9 mm, which are conventional examples, are indicated by black circles (●), and the oscillation efficiency was 75%. The triangle (Δ) indicates the case where the outer diameter φc was changed to 3.9 mm, 3.8 mm, and 3.7 mm, and their oscillation efficiencies were all 76%. A white circle (◯) indicates the case where the outer diameter φc is changed to 3.6 mm and 3.4 mm, and the oscillation efficiency thereof is 77% in all cases. From the above results, the inscribed circle diameter φa of the vane tip is set to 7.5 mm, 8.0 mm, and 8.5 mm, and the magnetic flux densities are 0.290 ± 0.010 Tesla, 0.250 ± 0.010 Tesla, It was found that the oscillation efficiency was 77% when the outer diameter φc was in the range from 3.4 mm to 3.6 mm for 0.220 ± 0.010 Tesla.
[0025]
Furthermore, the distribution of the electric field in the electron motion space is examined in detail, and the mutual distance G and the thickness T of the vane on the cathode side tip of the vane are examined. In FIG. 5, when the inscribed circle diameter φa of the vane tip is 8.0 mm, the magnetic flux density is 0.250 ± 0.010 Tesla, and the outer diameter φc of the coiled filament 1 is 3.6 mm, G and The results of measuring the oscillation efficiency using the T ratio G / (G + T) as a parameter are shown. When G / (G + T) = 0.20, 0.22, and 0.25, the oscillation efficiency was improved to 77.8%, 78.1%, and 77.5%, respectively, with the average value of 10 samples.
[0026]
Further, since the oscillation efficiency is lowered when an electric field is generated in the height direction of the vane, the height H of the vane 7 in the tube axis direction was examined. FIG. 6 shows the results shown in FIGS. 2 to 5 under the conditions when the oscillation efficiency is maximum, that is, the magnetic flux density is 0.250 ± 0.010 Tesla, the inscribed circle at the tip of the vane. The result of examining the height H in the tube axis direction of the vane 7 when the diameter φa is 8.0 mm, the outer diameter φc of the coiled filament 1 is 3.6 mm, and G / (G + T) = 0.22 is shown. From this figure, it has been found that the oscillation efficiency is approximately 78% when the height dimension H of the vane 7 in the tube axis direction is 9.0 mm or more.
[0027]
Table 1 compares the present invention and a conventional magnetron, and shows measurement results of output and oscillation efficiency at an input anode voltage of 4.5 kV and an anode current of 300 mA.
[0028]
[Table 1]
[0029]
【The invention's effect】
As described above in detail, the present invention improves the electronic efficiency ηe without increasing the anode voltage by increasing the magnetic flux density and optimizing the dimensions of each part of the magnetron related to the electron motion space, and the oscillation efficiency η It is possible to provide a high-efficiency magnetron that can greatly improve the above.
[Brief description of the drawings]
FIG. 1A is an enlarged cross-sectional view of a main part of a magnetron of the present invention, and FIG. 1B is a diagram showing a mutual interval G between the cathode side tips of adjacent vanes and a thickness T of the vanes of the present invention. FIG. 3 is a diagram showing the relationship between the diameter of the inscribed circle at the vane tip and the magnetic flux density in comparison with the prior art in the present invention. FIG. 4 is a graph showing the efficiency of oscillation efficiency between the diameter φa of the inscribed circle at the vane tip and the outer diameter φc of the coiled filament in comparison with the prior art. FIG. 6 is a graph showing the relationship between the ratio of the gap G to the thickness T at the vane cathode side tip and the oscillation efficiency in comparison with the conventional example. FIG. 6 shows the relationship between the height in the vane tube axial direction of the present invention and the oscillation efficiency. [Fig. 7] Cross-sectional view of a conventional magnetron [Explanation of symbols]
1 coiled filament 4 center lead 6 anode cylinder 7 vane 9 magnetic pole 10 magnetic pole 17 electron motion space 19 annular permanent magnet 20 annular permanent magnet D1 annular permanent magnet outer diameter D2 annular permanent magnet inner diameter D3 annular permanent magnet outer diameter D4 annular Inner diameter L1 of permanent magnet Thickness L2 of annular permanent magnet Thickness of annular permanent magnet φa Diameter of vane cathode side tip inscribed circle φc Outer diameter G of coiled filament T Thickness H Vane's axial dimension

Claims (1)

陽極円筒と、この陽極円筒の内壁面に固着された複数個のベインとで形成される陽極部と、前記陽極部の同軸的中心部に設けられたコイル状フィラメントからなる陰極部と、前記陽極部の管軸方向上下に配設された一対の磁極と、この一対の磁極と磁気的に結合配置されて磁気回路を構成する環状永久磁石と、前記磁極の各管軸方向外方にそれぞれ配設された入力部と出力部とを具備し、前記陽極部を構成するベイン先端部の内接円の直径が7.5〜8.5mmの範囲内であり、前記コイル状フィラメントの外径が3.4〜3.6mmの範囲内であり、かつ前記ベインの隣り合う陰極側先端部の相互間隔Gとベインの厚さTとの比をG/(G+T)=0.20〜0.25としたことを特徴とするマグネトロン。An anode portion formed of an anode cylinder and a plurality of vanes fixed to the inner wall surface of the anode cylinder; a cathode portion formed of a coiled filament provided in a coaxial central portion of the anode portion; and the anode A pair of magnetic poles disposed above and below the tube axis in the tube axis, an annular permanent magnet that is magnetically coupled to the pair of magnetic poles to form a magnetic circuit, and an outer side of each of the magnetic poles in the tube axis direction. An input part and an output part provided, the diameter of the inscribed circle of the vane tip part constituting the anode part is in the range of 7.5 to 8.5 mm, and the outer diameter of the coiled filament is The ratio of the gap G between the adjacent cathode side tips of the vane and the thickness T of the vane is within the range of 3.4 to 3.6 mm, and G / (G + T) = 0.20 to 0.25. magnetron, characterized in that the the.
JP2001326281A 2001-10-24 2001-10-24 Magnetron Expired - Lifetime JP3925153B2 (en)

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KR10-2002-0049385A KR100485725B1 (en) 2001-08-22 2002-08-21 Magnetron
CNB021437262A CN1224996C (en) 2001-08-22 2002-08-22 Magnetron
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KR100651905B1 (en) * 2005-03-29 2006-12-01 엘지전자 주식회사 magnetron
JP4898316B2 (en) * 2006-06-19 2012-03-14 東芝ホクト電子株式会社 Magnetron
JP4503639B2 (en) 2007-09-11 2010-07-14 東芝ホクト電子株式会社 Magnetron for microwave oven
CN102339707B (en) * 2011-08-03 2014-01-01 广东威特真空电子制造有限公司 Magnetron with high output power
JP6261898B2 (en) * 2013-07-05 2018-01-17 東芝ホクト電子株式会社 Plasma light emitting device and electromagnetic wave generator used therefor
JP6261899B2 (en) * 2013-07-05 2018-01-17 東芝ホクト電子株式会社 Plasma light emitting device and electromagnetic wave generator used therefor
JP6261897B2 (en) * 2013-07-05 2018-01-17 東芝ホクト電子株式会社 Plasma light emitting device and electromagnetic wave generator used therefor
JP5805842B1 (en) 2014-12-03 2015-11-10 東芝ホクト電子株式会社 Magnetron

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